When providing a light production system for a projector, it is important that the light emitted from the light production system be generally uniform to provide a non-distracting viewing experience. Unfortunately light emitted from lamps such as elliptical lamps and parabolic lamps is generally not uniform, with the center of the lamp being brightest, the brightness decreasing towards the edges. In addition, projection lens systems tend to have a relative illumination profile that is brighter towards the center of a projected image. Hence, even with the use of integrators, the overall image that is projected onto a screen has a tendency towards being brighter at the center than at the edges. When the corner point brightness becomes too low in comparison to the center point brightness, the image may appear to have an undesirable “hot spot” (or high brightness region) in the center screen position. Not only is this unacceptable for a viewer, but will cause a projector to fail industry standards, such as those set by the Digital Cinema Initiative (DCI).
While the problem may be addressed by modulating the image via an electronic correction (e.g. in an image generating light modulation component), this solution is both expensive and complex, requiring considerable use of system resources and is further only applicable to digital projectors.